As the level of technology increases, the options for communications have become more varied. For example, in the last 30 years in the telecommunications industry, personal communications have evolved from a home having a single rotary dial telephone, to a home having multiple telephone, cable and/or fiber optic lines that accommodate both voice and data. Additionally, cellular phones and Wi-Fi have added a mobile element to communications. With the advent of the Internet, IP networks have become an area in which these, and other services, and technologies are seen to be converging.
To accommodate the new and different ways in which IP networks are being used to provide various services, new network architectures are being developed and standardized. IP Multimedia Subsystem (IMS) is an architectural framework designed for delivering IP multimedia services to an end user. The IMS architecture has evolved into a service-independent topology which uses IP protocols, e.g., Session Initiation Protocol (SIP) signaling, to provide a convergence mechanism for disparate systems. In part this is accomplished via the provision of a horizontal control layer which isolates the access network from the service layer.
Lawful intercept functionality in telecommunication nodes is a legal requirement in many countries. Such intercept capability enables law enforcement agencies to obtain copies of and/or “listen in” to calls placed by (or to) identified individuals or phones. Thus, each telecommunication technology has specified its own solution to address the lawful interception legal requirements. On a high level, the lawful intercept functionality generally requires that nodes that handle the call control signaling be able to replicate the call data for intercept purposes and that nodes that handle the media flow be able to replicate the call content for intercept purposes.
The above described IMS technology also specifies its own solution for meeting lawful intercept requirements. For example, in the call control or signaling plane, a call session control function (CSCF) node is required to replicate the call data for lawful interception as shown in FIG. 1. Therein, a plurality of law enforcement monitoring functions (LEMF) 10, e.g., each associated with a government agency or police bureau, has access to an HI1 interface over which it can request that call interception be performed for a particular user, telephone number or device to initiate tracking of that entity. These requests are signaled over respective HI1 interfaces to an administrative function (ADMF) 12. The ADMF 12 correlates the requests from the various agencies via a mediation function and instructs the IMS node, in this example the P/S CSCF node 14, via an X1 or X1—1 interface to start intercepting (replicating) the control signaling associated with the target's calls that pass through, or are controlled by, that node.
When a call is initiated from or to a lawful intercept target that has been properly identified by the ADMF 12, the P/S CSCF node 14 replicates the control signaling associated with the intercepted call and forwards it on to the LEMF 10 over an X2 interface via a delivery function 16 and HI2 interface. Similar functionality is performed in IMS systems by the GPRS support node (GSN) 18, shown in FIG. 2, for intercepting the content portion (payload data) of a lawful intercept target's calls, which content is replicated and passed back to the requesting law enforcement via an X3 interface and delivery function 20.
Packet cable access technology also provides multimedia services and its specification can be found in the PacketCable forum (www.packetcable.com). Since packet cable provides telecommunication services, such systems must also comply with the legal requirements for lawful call intercept. Earlier versions of packet cable technology specified that certain packet cable nodes would be responsible for handling the call control associated with lawful intercept. For example, Packet Cable Version 1.5 specified a solution to address the lawful intercept legal requirements wherein a Cable Modem Termination System (CMTS) node replicated the call content for intercepted calls and a Call Management System (CMS) node replicated the call data for intercepted calls, as specified in a standard specification referenced as PKT-SP-ESP1.5-I02-070412. This architecture is described in more detail below.
More recently, Version 2.0 of the Packet Cable specification has been introduced. This version of the packet cable specification added IMS elements into its architecture as part of the convergence of these technologies, using some aspects of IMS verbatim and modifying other aspects of IMS to address cable specific issues. However Packet Cable Version 2.0 did not adopt the lawful intercept solution described above in FIGS. 1 and 2 for IMS, but instead evolved the existing packet cable lawful interception solution to handle the legal requirements associated with call intercept, as specified in a standard specification referenced as PKT-SP-ES-INF-I04-080425. Thus, in order to upgrade their networks from Packet Cable Version 1.5 to Packet Cable Version 2.0 to provide multimedia call service, network service providers also need to upgrade, for example, the CMTS node to provide for call interception of multimedia calls. This node upgrade may be time consuming and expensive.
Accordingly, it would be desirable to provide methods, systems and devices for supporting the required lawful interception functionality in packet cable networks without requiring upgrade of existing packet cable nodes, while also adhering to requirements associated with call security and privacy.